use less unstable dependencies

examples/minimal.rs

@@ -0,0 +1,35 @@
+#![no_main] // <- IMPORTANT!
+#![no_std]
+
+#[macro_use]
+extern crate cortex_m_rt;
+extern crate panic_abort;
+
+use core::ptr;
+
+// user entry point
+main!(main);
+
+fn main() -> ! {
+    loop {
+        unsafe {
+            // NOTE side affect to avoid UB
+            ptr::read_volatile(0x2000_0000 as *const u32);
+        }
+    }
+}
+
+// define the default exception handler
+exception!(DefaultHandler, deh);
+
+fn deh(_nr: u8) -> ! {
+    loop {
+        unsafe {
+            // NOTE side affect to avoid UB
+            ptr::read_volatile(0x2000_0004 as *const u32);
+        }
+    }
+}
+
+// bind all interrupts to the default exception handler
+interrupts!(DefaultHandler);